问题
选择题
— The window must have taken you quite a lot of time that day.
— Right. They____ for weeks.
A．haven’t been cleaned
B．hadn’t been cleaned
C．didn’t clean
D．haven’t cleaned
答案
答案：B
考查时态。句意：那天擦窗户一定花了你很长时间吧。是的，他们已经好几周没擦了。must have taken表示的是对去事情肯定的推测，在这之前发生的动作应用过去完成时态。所以选B。